From patchwork Fri Dec 1 14:31:34 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Halil Pasic X-Patchwork-Id: 10087479 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 04FA86035E for ; Fri, 1 Dec 2017 17:01:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E7F9B265B9 for ; Fri, 1 Dec 2017 17:01:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DCA1F28948; Fri, 1 Dec 2017 17:01:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5043B265B9 for ; Fri, 1 Dec 2017 17:01:17 +0000 (UTC) Received: from localhost ([::1]:58773 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKoge-0001yp-CH for patchwork-qemu-devel@patchwork.kernel.org; Fri, 01 Dec 2017 12:01:16 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44931) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKnnY-0007pe-Oe for qemu-devel@nongnu.org; Fri, 01 Dec 2017 11:04:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eKnnH-0007M3-UL for qemu-devel@nongnu.org; Fri, 01 Dec 2017 11:04:20 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:34630) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eKnnH-0007Kp-HY for qemu-devel@nongnu.org; Fri, 01 Dec 2017 11:04:03 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vB1ETOIF070902 for ; Fri, 1 Dec 2017 09:31:56 -0500 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ek86kjrcb-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 01 Dec 2017 09:31:55 -0500 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 1 Dec 2017 14:31:49 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id vB1EVmdt57737236; Fri, 1 Dec 2017 14:31:48 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8FFA811C064; Fri, 1 Dec 2017 14:26:20 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3F63F11C052; Fri, 1 Dec 2017 14:26:20 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Fri, 1 Dec 2017 14:26:20 +0000 (GMT) From: Halil Pasic To: Boris Fiuczynski , Cornelia Huck Date: Fri, 1 Dec 2017 15:31:34 +0100 X-Mailer: git-send-email 2.13.5 In-Reply-To: <20171201143136.62497-1-pasic@linux.vnet.ibm.com> References: <20171201143136.62497-1-pasic@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17120114-0012-0000-0000-00000593DA26 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17120114-0013-0000-0000-0000190ECD88 Message-Id: <20171201143136.62497-2-pasic@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-12-01_03:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1712010164 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.156.1 Subject: [Qemu-devel] [PATCH 1/3] s390x/css: unrestrict cssids X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Shalini Chellathurai Saroja , Halil Pasic , qemu-devel@nongnu.org, Christian Borntraeger , qemu-s390x@nongnu.org, Dong Jia Shi Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP The default css 0xfe is currently restricted to virtual subchannel devices. The hope when the decision was made was, that non-virtual subchannel devices will come around when guests can exploit multiple channel subsystems. Since current guests don't do that, the pain of the partitioned (cssid) namespace outweighs the gain. The default css 0xfe is currently restricted to virtual subchannel devices. The hope when the decision was made was, that non-virtual subchannel devices will come around when guest can exploit multiple channel subsystems. Since the guests generally don't do, the pain of the partitioned (cssid) namespace outweighs the gain. Let us remove the corresponding restrictions (virtual devices can be put only in 0xfe and non-virtual devices in any css except the 0xfe -- while s390-squash-mcss then remaps everything to cssid 0). At the same time, change our schema for generating css bus ids to put both virtual and non-virtual devices into the default css (spilling over into other css images, if needed). The intention is to deprecate s390-squash-mcss. Whit this change devices without a specified devno won't end up hidden to guests not supporting multiple channel subsystems, unless this can not be avoided (default css full). Deprecaton of s390-squash-mcss and indicating the changes via QMP is expected to follow soon (as separate commits). The adverse effect of getting rid of the restriction on migration should not be too severe. Vfio-ccw devices are not live-migratable yet, and for virtual devices using the extra freedom would only make sense with the aforementioned guest support in place. The auto-generated bus ids are affected by both changes. We hope to not encounter any auto-generated bus ids in production as Libvirt is always explicit about the bus id. Since 8ed179c937 ("s390x/css: catch section mismatch on load", 2017-05-18) the worst that can happen because the same device ended up having a different bus id is a cleanly failed migration. I find it hard to reason about the impact of changed auto-generated bus ids on migration for command line users as I don't know which rules is such an user supposed to follow. Another pain-point is down- or upgrade of QEMU for command line users. The old way and the new way of doing vfio-ccw are mutually incompatible. Libvirt is only going to support the new way, so for libvirt users, the possible problems at QEMU downgrade are the following. If a domain contains virtual devices placed into a css different than 0xfe the domain will refuse to start with a QEMU not having this patch. Putting devices into a css different that 0xfe however won't make much sense in the near future (guest support). Libvirt will refuse to do vfio-ccw with a QEMU not having this patch. This is business as usual. Signed-off-by: Halil Pasic Acked-by: Christian Borntraeger Reviewed-by: Dong Jia Shi --- Hi! I've factored out the announcing via QMP interface stuff to ease review. I would not mind the two being squashed together before this hits main, as I would much prefer having the two as one (atomic) change. But the second part turned out so controversial, that splitting is expected to benefit the review process. v2 -> v3: * factored out announcing into a separate patch * reworded commit message * removed outdated comment about squash v1 -> v2: * changed ccw bus id generation too (see commit message) * moved the property to the machine (see cover letter) * added a description to the property --- hw/s390x/3270-ccw.c | 2 +- hw/s390x/css.c | 28 ++++------------------------ hw/s390x/s390-ccw.c | 2 +- hw/s390x/s390-virtio-ccw.c | 1 - hw/s390x/virtio-ccw.c | 2 +- include/hw/s390x/css.h | 12 ++++-------- 6 files changed, 11 insertions(+), 36 deletions(-) diff --git a/hw/s390x/3270-ccw.c b/hw/s390x/3270-ccw.c index 081e3ef6f4..3af13ea027 100644 --- a/hw/s390x/3270-ccw.c +++ b/hw/s390x/3270-ccw.c @@ -104,7 +104,7 @@ static void emulated_ccw_3270_realize(DeviceState *ds, Error **errp) SubchDev *sch; Error *err = NULL; - sch = css_create_sch(cdev->devno, true, cbus->squash_mcss, errp); + sch = css_create_sch(cdev->devno, cbus->squash_mcss, errp); if (!sch) { return; } diff --git a/hw/s390x/css.c b/hw/s390x/css.c index f6b5c807cd..cd26f32050 100644 --- a/hw/s390x/css.c +++ b/hw/s390x/css.c @@ -2370,22 +2370,12 @@ const PropertyInfo css_devid_ro_propinfo = { .get = get_css_devid, }; -SubchDev *css_create_sch(CssDevId bus_id, bool is_virtual, bool squash_mcss, - Error **errp) +SubchDev *css_create_sch(CssDevId bus_id, bool squash_mcss, Error **errp) { uint16_t schid = 0; SubchDev *sch; if (bus_id.valid) { - if (is_virtual != (bus_id.cssid == VIRTUAL_CSSID)) { - error_setg(errp, "cssid %hhx not valid for %s devices", - bus_id.cssid, - (is_virtual ? "virtual" : "non-virtual")); - return NULL; - } - } - - if (bus_id.valid) { if (squash_mcss) { bus_id.cssid = channel_subsys.default_cssid; } else if (!channel_subsys.css[bus_id.cssid]) { @@ -2396,19 +2386,8 @@ SubchDev *css_create_sch(CssDevId bus_id, bool is_virtual, bool squash_mcss, bus_id.devid, &schid, errp)) { return NULL; } - } else if (squash_mcss || is_virtual) { - bus_id.cssid = channel_subsys.default_cssid; - - if (!css_find_free_subch_and_devno(bus_id.cssid, &bus_id.ssid, - &bus_id.devid, &schid, errp)) { - return NULL; - } } else { - for (bus_id.cssid = 0; bus_id.cssid < MAX_CSSID; ++bus_id.cssid) { - if (bus_id.cssid == VIRTUAL_CSSID) { - continue; - } - + for (bus_id.cssid = channel_subsys.default_cssid;;) { if (!channel_subsys.css[bus_id.cssid]) { css_create_css_image(bus_id.cssid, false); } @@ -2418,7 +2397,8 @@ SubchDev *css_create_sch(CssDevId bus_id, bool is_virtual, bool squash_mcss, NULL)) { break; } - if (bus_id.cssid == MAX_CSSID) { + bus_id.cssid = (bus_id.cssid + 1) % MAX_CSSID; + if (bus_id.cssid == channel_subsys.default_cssid) { error_setg(errp, "Virtual channel subsystem is full!"); return NULL; } diff --git a/hw/s390x/s390-ccw.c b/hw/s390x/s390-ccw.c index 0ef232ec27..4a9d4d2534 100644 --- a/hw/s390x/s390-ccw.c +++ b/hw/s390x/s390-ccw.c @@ -77,7 +77,7 @@ static void s390_ccw_realize(S390CCWDevice *cdev, char *sysfsdev, Error **errp) goto out_err_propagate; } - sch = css_create_sch(ccw_dev->devno, false, cbus->squash_mcss, &err); + sch = css_create_sch(ccw_dev->devno, cbus->squash_mcss, &err); if (!sch) { goto out_mdevid_free; } diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index 6a57f94197..4d65a50334 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -302,7 +302,6 @@ static void ccw_init(MachineState *machine) /* * Non mcss-e enabled guests only see the devices from the default * css, which is determined by the value of the squash_mcss property. - * Note: we must not squash non virtual devices to css 0xFE. */ if (css_bus->squash_mcss) { ret = css_create_css_image(0, true); diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c index 184515ce94..3dd902a664 100644 --- a/hw/s390x/virtio-ccw.c +++ b/hw/s390x/virtio-ccw.c @@ -701,7 +701,7 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp) SubchDev *sch; Error *err = NULL; - sch = css_create_sch(ccw_dev->devno, true, cbus->squash_mcss, errp); + sch = css_create_sch(ccw_dev->devno, cbus->squash_mcss, errp); if (!sch) { return; } diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h index ab6ebe66b5..53c270a216 100644 --- a/include/hw/s390x/css.h +++ b/include/hw/s390x/css.h @@ -272,12 +272,9 @@ extern const PropertyInfo css_devid_ro_propinfo; * default css image for it. * If @p bus_id is valid, and @p squash_mcss is false, verify that it is * not already in use, and find a free devno for it. - * If @p bus_id is not valid, and if either @p squash_mcss or @p is_virtual - * is true, find a free subchannel id and device number across all - * subchannel sets from the default css image. - * If @p bus_id is not valid, and if both @p squash_mcss and @p is_virtual - * are false, find a non-full css image and find a free subchannel id and - * device number across all subchannel sets from it. + * If @p bus_id is not valid find a free subchannel id and device number + * across all subchannel sets and all css images starting from the default + * css image. * * If either of the former actions succeed, allocate a subchannel structure, * initialise it with the bus id, subchannel id and device number, register @@ -286,8 +283,7 @@ extern const PropertyInfo css_devid_ro_propinfo; * The caller becomes owner of the returned subchannel structure and * is responsible for unregistering and freeing it. */ -SubchDev *css_create_sch(CssDevId bus_id, bool is_virtual, bool squash_mcss, - Error **errp); +SubchDev *css_create_sch(CssDevId bus_id, bool squash_mcss, Error **errp); /** Turn on css migration */ void css_register_vmstate(void);